In conventional magnetic tape recorder/players of, for instance, the cassette type, the magnetic head is interconnected with the function control levers; so that when either one of the control levers for operating the tape recorder in the recording or reproducing modes is depressed, the magnetic head is introduced into the space in which a cassette has been inserted and is brought into contact with the magnetic tape in the cassette.
However, if either of the above-mentioned function control levers is depressed before the insertion of a cassette, the magnetic head will be introduced into the space in which the cassette has not yet been inserted. This not only hampers the subsequent insertion of a cassette, but also may result in damage to either the magnetic head or the magnetic tape or both. As a consequence, it is desirable to provide a simple and effective means to prevent operation of the function control levers when no cassette is inserted into the recorder/player.